Chapter 7. Best Practices for RXT
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Optimizing Performance
Following are a few tips to achieve optimal performance from RXT drives and RXT
media.
Achieving Appropriate Transfer Speeds
RXT drives are designed to achieve transfer rates of up to 80 MB/sec when configured
as RAID 0 in an optimal environment (that is, with an optimal data source and optimal
performance from the server connected to the RXT350).
Tests have shown that speeds up to 80 MB/sec are achievable in optimized
environments.
Due to different read and write processes that must occur for RAID 1, RAID 5, and
RAID 1+0, the transfer rates for these configurations vary. A reasonable expectation for
these RAID levels is 50 MB/sec; make sure that you are achieving at least this level of
throughput no matter what RAID type you are using.
Checking Block Sizes
The RXT drives themselves cannot be configured to alter performance; all performance
tuning must be done with your operating system and backup software. To maximize
RXT performance, Spectra Logic recommends using a 256KB block size (or larger) in
your backup application. Block sizes smaller than this may show decreased
performance.
Note:
Block sizes larger than 256KB are not supported in Windows
operating systems with IBM drivers.
Note:
Block sizes should always be divisible by four (4).
Consult the documentation for your backup software for instructions on how to
configure the block size setting and other performance tuning options.
Enabling SCSI Disconnects
In most backup environments, SCSI disconnects are already enabled, which optimizes
backup performance. This setting should remain the same for RXT drives, since
RXT drives have substantially slower SCSI throughput if SCSI disconnects are disabled.
Consult your HBA’s user documentation for instructions on how to modify this option.
